Various medical devices formed from biodegradable polymers, particularly aliphatic polyesters such as polylactic acid, polyglycolic acid, and polycaprolactone, and copolymers thereof, are known. For example, a formed article in the form of a fiber has been applied to a suture thread or a bioabsorbable sheet.
Electrospinning (also referred to as an electric field spinning method) allows for the easy production of a fiber having a small fiber diameter. According to this production method, the surface area of a fibrous formed article can be increased to enhance adhesion to cells. Therefore, its applications to carriers for cell culture, scaffold materials for regenerative medicine, and the like have been studied.
Generally, it is known that a polyester is easily charged and that the half-life of the built-up charge is long. Accordingly, a fibrous formed article obtained by processing an aliphatic polyester into a fiber is likely to be charged and thus is not easy to use. Thus, a polyester fiber having excellent antistatic properties has been demanded.
However, biodegradable low-charging polyester fibers for in vivo use are heretofore unknown.
JP-A-9-157954 describes an antistatic fiber made of an antistatic polymer and a polyester copolymer. This fiber is naturally degradable and aimed to prevent pollution, and there is no description about in vivo use or use of a low-molecular-weight compound as an antistatic agent.
JP-A-8-231837 describes an antistatic polylactic acid obtained by adding a polyalkylene ether and an antistatic agent made of an aliphatic polyester other than polylactic acid to polylactic acid. However, there is no description about in vivo use or use of a low-molecular-weight compound as the antistatic agent.
WO06/022430 describes a fiber obtained by adding a phospholipid to polylactic acid, but nowhere describes a fiber having antistatic properties.